On Sat, Jul 03, 2021 at 06:38:27AM -0400, Jeff King wrote:
> On Sat, Jul 03, 2021 at 12:05:46PM +0200, René Scharfe wrote:
>
> > We use our standard allocation functions and macros (xcalloc,
> > ALLOC_ARRAY, REALLOC_ARRAY) in our version of khash.h. They terminate
> > the program on error, so code that's using them doesn't have to handle
> > allocation failures. Make this behavior explicit by replacing the code
> > that handles allocation errors in kh_resize_ and kh_put_ with BUG calls.
>
> Seems like a good idea.
>
> We're very sloppy about checking the "ret" field from kh_put_* for
> errors (it's a tri-state for "already existed", "newly added", or
> "error"). I think that's not a problem because as you show here, we
> can't actually hit the error case. This makes that much more obvious.
Actually a quad-state, looking at the code (it distinguishes "in table
but deleted", though I don't think I've ever seen a case where that is
useful).
> Two nits if we wanted to go further:
In patch form (mostly because I was curious if I was missing any cases;
I'd probably squash it in with yours):
diff --git a/khash.h b/khash.h
index 84ff7230b6..fad486c966 100644
--- a/khash.h
+++ b/khash.h
@@ -74,7 +74,7 @@ static const double __ac_HASH_UPPER = 0.77;
void kh_destroy_##name(kh_##name##_t *h); \
void kh_clear_##name(kh_##name##_t *h); \
khint_t kh_get_##name(const kh_##name##_t *h, khkey_t key); \
- int kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets); \
+ void kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets); \
khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret); \
void kh_del_##name(kh_##name##_t *h, khint_t x);
@@ -116,7 +116,7 @@ static const double __ac_HASH_UPPER = 0.77;
return __ac_iseither(h->flags, i)? h->n_buckets : i; \
} else return 0; \
} \
- SCOPE int kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets) \
+ SCOPE void kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets) \
{ /* This function uses 0.25*n_buckets bytes of working space instead of [sizeof(key_t+val_t)+.25]*n_buckets. */ \
khint32_t *new_flags = NULL; \
khint_t j = 1; \
@@ -173,18 +173,15 @@ static const double __ac_HASH_UPPER = 0.77;
h->n_occupied = h->size; \
h->upper_bound = (khint_t)(h->n_buckets * __ac_HASH_UPPER + 0.5); \
} \
- return 0; \
} \
SCOPE khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret) \
{ \
khint_t x; \
if (h->n_occupied >= h->upper_bound) { /* update the hash table */ \
if (h->n_buckets > (h->size<<1)) { \
- if (kh_resize_##name(h, h->n_buckets - 1) < 0) { /* clear "deleted" elements */ \
- BUG("kh_resize_" #name " failed"); \
- } \
- } else if (kh_resize_##name(h, h->n_buckets + 1) < 0) { /* expand the hash table */ \
- BUG("kh_resize_" #name " failed"); \
+ kh_resize_##name(h, h->n_buckets - 1); /* clear "deleted" elements */ \
+ } else { \
+ kh_resize_##name(h, h->n_buckets + 1); /* expand the hash table */ \
} \
} /* TODO: to implement automatically shrinking; resize() already support shrinking */ \
{ \
